Senior Game Producer Tom Ellis commented on X, formerly Twitter, about the issues happening with the Auction House in The War Within. They mentioned that there are plans to improve the situation with Maintenance while they work on a permanent solution to the core issue.
The WoW Auction House is a complex transactional system similar to that of Stock Exchanges worldwide. These systems are susceptible to small changes in transaction times, which can have cascading effects, leading to the whole system ending up stuck or incredibly slowing down almost to a halt, so it isn't surprising to see that such a change has impacted it so much. Hopefully, these changes coming with the next maintenance window, likely during the Weekly Reset, will remedy the issues until they can figure out ways to address the underlying issues.